The newer slums are like early-stage refugee camps: clusters of flimsy huts with blue tarpaulin roofs. The Mumbai-Hindi term for a slum - jhopadpatti - basically means a strip of huts (slumdwellers are jhopadpattiwallahs). In the older slums, mud huts have been replaced by brick houses, and floors added to make room for more workshops and bedrooms.

The worst corners are those that border on open land where the municipality dumps trash. I came upon one such corner on the edge of the Antop Hill slum, the area briefly seen in Slumdog Millionaire, when the hero meets his gangster brother at the top of a fancy new skyscraper. I walked from a newly-paved main street within the slum to a rubbish dump where children were picking rags. Here brick structures with corrugated iron roofs gave way to mud ones with tarpaulin covers. A municipal bulldozer sat motionless in a muddy, foul-smelling creek. Crowds of children ran out of the shacks to see the first foreigners to come to this part of the slum. All were clean-faced and wearing bright, clean clothes. One plump boy of about nine practised his English with me. I said to his aunt, who came from Uttar Pradesh in northern India, that the children were beautiful. She replied: "How can they be beautiful children when they are born and brought up in trash?"

The oldest and most infamous slum in Mumbai is Dharavi, the "Queen of Slums", which grew up around a fishing village on one of the city's original islands, beginning about 100 years ago. Sitting squarely in the centre of Mumbai, it is also the city's most prosperous slum; people actually commute to it for work.